CN106660871B

CN106660871B - Method and system for heat treating dispersible raw materials

Info

Publication number: CN106660871B
Application number: CN201580047966.3A
Authority: CN
Inventors: D·克莱格拉夫; S·弗里耶; H·布林克舒尔特
Original assignee: ThyssenKrupp AG; ThyssenKrupp Industrial Solutions AG
Current assignee: ThyssenKrupp AG; ThyssenKrupp Industrial Solutions AG
Priority date: 2014-09-11
Filing date: 2015-09-09
Publication date: 2020-03-17
Anticipated expiration: 2035-09-09
Also published as: JP2017535501A; WO2016038076A1; US20170260089A1; KR20170056590A; CN106660871A; JP6456485B2; EP3191425A1; US10370293B2; DK3191425T3; KR102049158B1; EP3191425B1; DE102014113127A1

Abstract

The invention relates to a method for heat treating dispersible raw materials, wherein the raw materials are introduced into a riser filled with hot gas, in which riser the raw materials are heat treated by the hot gas. Furthermore, at least one fuel is supplied to the riser, wherein the fuel initially rests in a fuel conditioning zone on at least one support surface, where it is contacted with a portion of the hot gas mixed with the raw material, thus drying and/or at least partially degassing and/or at least partially reacting, and is thereafter transferred to the riser.

Description

Method and system for heat treating dispersible raw materials

Technical Field

The present invention relates to a method and a system for heat treating dispersible raw materials, wherein the raw materials are introduced into a riser pipe being perfused with one or more hot gases and the heat treatment is carried out in the riser pipe by means of the one or more hot gases, respectively.

Background

Such heat treatment is carried out, for example, in the calcination of cement raw materials in the production of cement clinker. The required thermal energy is provided by fuel burned in a separate combustion chamber, which is connected for example to a riser (DE 102004045510 a 1). A similar concept is known from DE 19535312 a1, which discloses a reactor coupled to a discharge line, which reactor produces combustible gases from waste material, in particular from used tires. The reactor in this document is constructed in the form of a gasification reactor and is connected to a cooler of the cement clinker system by a tertiary air line, so that at least a part of the exhaust gases of the cooler can be used as gasification agent in the reactor. According to DE 102005052753 a1, an additional combustion zone is formed in the form of insufficient combustion.

In all these combustion chambers of various configurations, the hot exhaust gases of the cooler are used to react the fuel, wherein the hot gases produced are supplied to the calciner. Wherein raw meal is used to adjust the temperature. A disadvantage of these concepts is the high complexity of the equipment associated with the supply of hot exhaust gases and raw meal to the cooler via separate lines. In many existing systems, the supply of raw meal particularly prevents the innovation of the technology, since there is no suitable height difference to allow the raw meal to be supplied by gravity.

In contrast, WO 2012/048159 a2 pursues another concept in which solid fuel (e.g. used tires) is burned directly in a riser by a pivot mounting facility. Although this method has the advantage that the complexity of the devices associated with the tertiary air line can be reduced accordingly, the correspondingly high complexity of the installation equipment due to the extremely high temperatures must be taken into account.

Disclosure of Invention

The invention is therefore based on the object of reducing the complexity of the plant for the reaction of fuel for the heat treatment of dispersible raw materials in risers filled with hot gas.

According to the invention, this object is achieved by the features of

claims

1 and 8. Particular design embodiments of the present invention are the subject of other claims.

In the case of the method according to the invention for heat treating dispersible raw materials, the raw materials are introduced into a riser pipe filled with hot gas and the heat treatment is carried out in the riser pipe by the hot gas. Furthermore, at least one fuel is supplied to the riser, wherein the fuel initially rests in a fuel conditioning zone on at least one support surface, where it is contacted with a portion of the hot gas mixed with the raw material, thus drying and/or at least partially degassing and/or at least partially reacting, and is thereafter transferred to the riser.

The term "hot gas" is understood to mean in particular flue gases, most preferably flue gases from a furnace or from a heat treatment system, which may be mixed with other treatment gases.

The present invention thus uses hot gases to react the fuel, thereby eliminating the high complexity of the plant due to the correspondingly large size of the tertiary air line or the additional tertiary air line to the fuel conditioning area. A further advantage is that the temperature regulation in the case of fuel reactions is significantly facilitated by the lower oxygen content of the hot gases used. The entrained raw meal in the hot gas also avoids excessively high temperature peaks.

The invention is based on the idea that the fuel in the entire fuel conditioning zone is largely (i.e. at least 50%) dried and/or at least partly degassed and/or at least partly reacted by hot gases mixed with the starting material.

The fuel in the fuel conditioning zone is here preferably contacted with hot gases, at least 50%, preferably at least 60%, or at least 70%, or at least 80%, or most preferably at least 90% of which are formed by a portion of the hot gases mixed with the raw material. The remainder is formed, for example, by the gas transporting the fuel along the bearing surface and/or by the air supplied through the propulsion nozzle, wherein the air supplied through the propulsion nozzle can divert the flue gas into the fuel conditioning zone and/or the oxygen content of the hot gas in the zone where the fuel conditioning zone is set.

According to a preferred embodiment, at least one bearing surface of the fuel conditioning zone is arranged in the conditioning chamber leading to the riser, wherein a portion of the hot gas mixed with the raw material is diverted from the riser into the conditioning chamber and is brought into contact with the fuel. In this way, in particular, it is also possible to use secondary fuel or moist fuel, respectively, since the secondary fuel or moist fuel is first dried and at least partially degassed and reacted in the conditioning chamber. The fuel is preferably supplied to the support surface mechanically or by gravity. The dried and/or at least partially degassed fuel is then conveyed along the support surface in a mechanical or pneumatic manner and is dropped into or transferred to the riser, respectively, where it is then completely reacted or combusted, respectively.

Depending on the oxygen content of the hot gas filling the riser, it may be desirable to set the oxygen content of the hot gas in contact with the fuel in a targeted manner by adding an oxygen-containing gas in order to optimize the conditioning or reaction of the fuel, respectively. The addition of the oxygen-containing gas can also divert the hot gases into the conditioning chamber, so that the amount of hot gases in contact with the fuel in the fuel conditioning zone is thereby set in a targeted manner.

Furthermore, it is undesirable that the fuel has fully reacted in the fuel conditioning area, thereby distributing the energy input through the fuel across the length of the standpipe. Thus, the extent of reaction of the fuel should be less than 90%, preferably less than 70%, most preferably less than 50% while falling into the standpipe. It is also advantageous that the degree of degassing of the fuel while falling into the riser is at least 70%. Thereby ensuring that the fuel, which is then entrained by the hot gases in the riser, can still be fully reacted within the riser.

According to a further embodiment of the invention, it can be provided that the fuel located on the support surface is extinguished by inert material (for example sand or limestone raw meal) as required.

The system for heat treatment of dispersible raw materials according to the invention is provided with a riser for injection of hot gases, means for feeding in raw materials, and a fuel conditioning zone, wherein the fuel conditioning zone comprises means for feeding in fuel, at least one bearing surface for the fuel, and means for transporting the fuel along the bearing surface and transferring the fuel to the riser. The fuel conditioning zone is here connected to a riser pipe such that a portion of the hot gas mixed with the raw material reaches the fuel conditioning zone and is brought into contact with the fuel in the fuel conditioning zone, whereby the fuel is dried and/or at least partially degassed and/or at least partially reacted.

The means for feeding in fuel may for example comprise a screw conveyor and/or a gate and/or a pump and/or a tappet and/or a chute and/or a dividing wheel gate and/or a gate system. The means for transferring and transferring the fuel to the riser can be formed in the shape of a door or tappet for mechanical transfer and/or a blower or blower for pneumatic transfer. The motive nozzle may be arranged to divert a portion of the hot gas mixed with the raw material into the fuel conditioning zone. These nozzles can be charged with an oxygen-containing gas in order to set the oxygen content of the hot gas in the fuel conditioning region in a targeted manner.

In order to provide sufficient space for the fuel to react, the ratio of the diameter D of the standpipe to the depth T of the bearing surface for the fuel in the fuel conditioning region should be 5> D/T >1.5, preferably 3> D/T1.5. The inclination of the bearing surface of the fuel with respect to the horizontal should be +45 ° to-50 °, preferably 0 to-30 °, most preferably 0 to-10 °.

It has also proven to be advantageous if the bearing surface is formed by at least two successive steps, since as the fuel moves from one step to the other, a mixing or swirling of the fuel occurs, respectively, thereby ensuring a more rapid reaction. The ratio of the height of the fuel adjustment region to the depth of the bearing surface or step is preferably between 0.5 and 2, preferably between 0.75 and 1.5. Of course, it is also conceivable for the bearing surface to be formed by one platform and at least one step adjoining the platform, wherein the length of the individual step is 0.2 to 1 times, preferably 0.2 to 0.6 times, the length of the platform. The ratio of the width to the depth of the bearing surface is advantageously between 0.5 and 2.5, preferably between 1 and 2.

According to another exemplary embodiment, the fuel conditioning region is formed by a conditioning chamber arranged in a part of the riser pipe, which is arranged inclined with respect to the vertical, wherein at least one bearing surface for the fuel is formed by a correspondingly configured wall region of the riser pipe. Depending on the configuration of the fuel conditioning zone, a diversion device may be provided which diverts a portion of the hot gas mixed with the raw material into the fuel conditioning zone. These deflecting means can be formed, for example, by a propelling nozzle.

Further advantages and design embodiments of the invention are explained in more detail by the following description of several exemplary embodiments and the accompanying drawings.

Drawings

In the drawings:

FIG. 1 shows a schematic diagram of a system for producing cement clinker;

FIG. 2 shows a schematic diagram of a system for heat treating dispersible raw materials according to a first exemplary embodiment;

FIG. 3 shows a schematic diagram of a system for heat treating dispersible raw materials according to a second exemplary embodiment; and is

Fig. 4 shows a schematic view of a system for heat treating dispersible raw materials according to a third exemplary embodiment.

Detailed Description

Fig. 1 shows a system for producing cement clinker having a multi-stage preheater 100 for preheating cement raw meal 101, a calciner 102 for precalcining the preheated cement raw meal 103, a furnace 104 for firing the precalcined cement raw meal 105 to form cement clinker, and a cooler 106 for cooling the cement clinker. The hot gases 107 generated in the furnace 104 are first fed into the calciner 102 and then into the preheater 100. Further, the cooler off-gas 108 produced in the cooler 106 is used as combustion air in the calciner 102.

Various exemplary embodiments of the configuration of the calciner are shown by figures 2 to 4. However, these exemplary embodiments may also relate to other systems for the thermal treatment or chemical reaction (e.g., ore reduction) of dispersible raw materials, and thus are not limited to calciners.

The system for heat treatment of dispersible raw materials shown in fig. 2 has a riser pipe 2 filled with hot gas 1, means 3 for feeding raw meal 4, in particular preheated cement raw meal 103 of fig. 1, and a fuel conditioning area 5, which fuel conditioning area 5 is attached to the riser pipe 2 as a conditioning chamber and leads to the riser pipe 2. The control chamber has a support surface 7 for the fuel 11, which support surface 7 is formed by a platform 7a and two

steps

7b, 7c adjoining in the vertical pipe direction. Furthermore, a device 10 for feeding fuel 11 is provided, which device 10 in the exemplary embodiment shown comprises a pendulum lamella 12 and a screw 13.

Fuel 11 is pushed by means of the device 10 to the support surface 7. The raw material 4 to be heat treated is supplied to the lower region of the riser 1 by means 3. Furthermore, oxygen-containing combustion air 8 (e.g. cooler off-gas 107 according to fig. 1) may be supplied to the riser 2 by means 14. The conditioning chamber 6 is connected to the riser 2 so that a portion 1a of the hot gas 1 mixed with the raw material 4 reaches the conditioning chamber 6 in a counter-current manner and comes into contact in the conditioning chamber 6 with the fuel 11 resting on the supporting surface 7, said fuel 11 thus drying and/or partially degassing and/or at least partially reacting. After a sufficient dwell time on the platform 7a, the fuel is pushed to the step 7b to be resupplied with new fuel by the screw conveyor 13. In the region of the step,

air blowing devices

15, 16 are provided, which

air blowing devices

15, 16 deliver fuel from the step 7b to the step 7c or drop fuel from the step 7c into the riser 2, respectively. However, blowers, gates or lifters may also be used. The screw 13 and the

blowing devices

15, 16 are opened in a mutually adjusted manner by a controller (not shown in detail) such that the fuel stays in the fuel conditioning region 5 for a predetermined time and reacts in the desired manner in the fuel conditioning region 5.

A silo 9 for inert material 9a may further be provided, for example in the event of a sudden system stop, by covering the fuel bed with inert material (e.g. sand or limestone raw meal) so as to slow down or substantially stop the still continuous fuel reaction.

The fuel falling into the riser 2 entrains the hot gases and reacts further or burns, respectively. In this case, a "counterflow" effect is achieved in a particularly effective manner when the ratio of the diameter D of the riser 2 to the depth T of the bearing surface 7 for the fuel in the fuel conditioning region 5 is 5> D/T >1.5, preferably 3> D/T >1.5, wherein a portion 1a of the hot gas 1 flowing upwards in the riser 2 reaches the conditioning chamber 6.

Fig. 3 shows an exemplary embodiment in which the regulating chamber 6 'is again open to the riser 2'. The device 10 'for feeding fuel is formed again by the pendulum flaps 12', 13 'and the chute 18', so that the fuel can be fed by gravity. Although the platform 7a of the bearing surface 7 of the first exemplary embodiment is arranged horizontally, the platform 7' a of the bearing surface 7' according to the exemplary embodiment of fig. 2 is inclined, wherein two horizontally configured steps 7' b, 7' c are again provided adjacent to the platform 7' a, wherein, however, steps with inclined bearing surfaces are also conceivable. The angle of inclination here may be from-45 ° to +50 °, preferably from 0 to-30 °, most preferably from 0 to-10 °. Conveniently, the degree of tilt is such that the fuel cannot slide downwards in an automatic manner.

Furthermore, in the exemplary embodiment shown, a device 19 'is provided for conveying the fuel 11' along the bearing surface 7', said device 19' being formed here by a door. In the stepped region, air blowing devices 15 ', 16' are again arranged. The inclined arrangement of the platform 7 'a has the advantage of facilitating the transport of the fuel 11'. Furthermore, the diversion of the portion 1 'a of hot gas 1' mixed with raw material 4 'can be facilitated by adjusting the geometry of the chamber 6'. To further facilitate this turning, a propulsion nozzle 20 ' is provided in the region of the conditioning chamber 6, said propulsion nozzle 20 ' being arranged in such a way as to cause a portion of the hot gas 1 ' mixed with the raw material 4 ' to enter the conditioning chamber 6 '.

A particularly efficient fuel reaction takes place in the region of the fuel control region when the ratio between the height H of the fuel control region 5, 5' and the depth T of the bearing surface is between 0.5 and 2, preferably between 0.75 and 1.5. If, as is the case with the two exemplary embodiments, the bearing surface 7, 7' is formed by one platform 7a, 7' a and at least one

step

7b, 7c, 7' b, 7' c adjoining the platform 7a, 7' a, the depth t of the step is preferably the depth t of the platform_T0.2 to 1 times, preferably 0.2 to 0.6 times. For the ratio of the width of the bearing surfaces 7, 7' to the depth T, values between 0.5 and 2.5, preferably between 1 and 2, have proved to be advantageous.

In the case of the exemplary embodiment according to fig. 4, the fuel conditioning region 5 "is formed by a conditioning chamber 6" arranged in a portion of the riser 2 ", which riser 2" is arranged inclined with respect to the vertical, wherein the bearing surface 7 "for the fuel is formed at least partially by an outwardly offset wall region of the riser 2", which wall region is formed in the exemplary embodiment shown only by the obliquely configured steps 7 "b, 7" c, 7 "d, 7" e. Due to the inclination of the steps, a simple blower is sufficient to deliver the fuel. The device 10' for feeding fuel 11 "is formed here by a cellular wheel sluice.

In the context of the present invention, the design embodiments shown in the three exemplary embodiments (for example the design embodiments of the bearing surfaces or the type of supply and delivery of fuel) can be combined with one another in any desired manner.

Claims

1. A method for the heat treatment of dispersible raw materials (4, 4 '), wherein the raw materials are introduced into a riser (2, 2') filled with hot gas (1, 1 ') and the heat treatment is carried out in the riser (2, 2') by the hot gas, and wherein at least one fuel (11, 11 ') is supplied to the riser, wherein the fuel first rests on at least one bearing surface in a fuel conditioning zone (5, 5'),

wherein the fuel (11, 11 ', 11 ") in the fuel conditioning zone is contacted with a portion of hot gas (1a, 1' a, 1" a) mixed with the raw material, thereby dried and/or at least partially degassed and/or at least partially reacted, and then transferred to the riser, characterized in that,

the fuel (11, 11 ') in the fuel conditioning zone is in contact with hot gases, at least 50% of which are formed by a portion of hot gases (1a, 1' a) mixed with raw material, wherein

At least one bearing surface (7, 7 ') of the fuel conditioning zone is arranged in a conditioning chamber (6, 6') leading to the riser (2, 2 '), wherein a portion of the hot gas (1, 1') mixed with raw material is diverted into the conditioning chamber and brought into contact with the fuel.

2. Method according to claim 1, characterized in that the fuel (11, 11', 11 ") is supplied to the support surface mechanically or by gravity.

3. Method according to claim 1, characterized in that the dried and/or at least partially degassed fuel (11, 11', 11 ") is transported along the support surface mechanically or pneumatically and then transferred to the riser pipe.

4. The method according to claim 1, characterized in that the amount of hot gas (1 'a) mixed with raw material and contacted with the fuel (11') in the fuel conditioning zone (5 ') is set in a targeted manner by adding an oxygen-containing gas (20').

5. Method according to claim 1, characterized in that the combustion reaction of the fuel (11, 11', 11 ") on the support surface can be slowed down or completely stopped by inert material.

6. A system for the heat treatment of dispersible raw materials (4, 4 ') having a riser (2, 2') filled with hot gas (1, 1 '), means (3, 3') for adding the raw materials (4, 4 ') and a fuel conditioning zone (5, 5') connected to the riser (2, 2 '), said fuel conditioning zone (5, 5') comprising means (10, 10 ') for adding fuel (11, 11'), at least one bearing surface (7, 7 ') for the fuel and means for transporting the fuel along the bearing surface and transferring the fuel to the riser, wherein the at least one bearing surface (7, 7') of the fuel conditioning zone is arranged in a conditioning chamber (6, 7 '), which leads to the riser (2, 2') 6', 6') of the group consisting of,

characterized in that the system is provided with a diverting device which diverts a portion of the hot gas mixed with the raw material into a fuel conditioning zone, thereby drying and/or at least partially degassing and/or at least partially reacting the fuel.

7. System according to claim 6, characterized in that the means (10, 10', 10 ") for feeding fuel comprise a screw conveyor and/or a gate and/or a pump and/or a tappet and/or a chute and/or a cellular wheel gate and/or a flap system.

8. System according to claim 6, characterized in that the means (9 ') for transferring and transferring the fuel to the riser (2') are shaped in the shape of a door or tappet for mechanical transfer and/or a blowing means or blower for pneumatic transfer.

9. A system according to claim 6, characterized in that at least one propulsion nozzle (20 ') is arranged in the fuel conditioning zone (5'), said propulsion nozzle (20 ') diverting a portion of the hot gas (1' a) mixed with raw material into the fuel conditioning zone.

10. A system according to claim 6, characterized in that the ratio of the diameter (D) of the riser (2, 2', 2 ") to the depth (T) of the bearing surface (7, 7', 7") of the fuel in the fuel conditioning area is 5> D/T > 1.5.

11. A system according to claim 7, characterized in that the ratio of the diameter (D) of the riser (2, 2', 2 ") to the depth (T) of the bearing surface (7, 7', 7") of the fuel in the fuel conditioning area is 3> D/T > 1.5.

12. System according to claim 6, characterized in that the support surface (7, 7', 7 ") is formed by at least two successive steps (7a, 7b, 7 c; 7' a, 7' b, 7' c; 7" a, 7 "b, 7" c) and/or by one platform (7a, 7' a, 7 "a) and at least one step adjoining the platform.

13. System according to claim 6, characterized in that the fuel conditioning area (5 ") is formed by a conditioning chamber (6") arranged in a part of the riser (2 "), which riser (2") is arranged inclined with respect to the vertical, and that at least one bearing surface (7 ") for the fuel is formed by an outwardly offset wall area of the riser (2").